K 10
svn:author
V 5
markj
K 8
svn:date
V 27
2021-01-06T14:58:31.247061Z
K 7
svn:log
V 1000
netgraph: Fix ng_ether's shutdown handing

When tearing down a VNET, netgraph sends shutdown messages to all of the
nodes before detaching interfaces (SI_SUB_NETGRAPH comes before
SI_SUB_INIT_IF in teardown order).  ng_ether nodes handle this by
destroying themselves without detaching from the parent ifnet.  Then,
when ifnets go away they detach their ng_ether nodes again, triggering a
use-after-free.

Handle this by modifying ng_ether_shutdown() to detach from the ifnet.
If the shutdown was triggered by an ifnet being destroyed, we will clear
priv->ifp in the ng_ether detach callback, so priv->ifp may be NULL.

Also get rid of the printf in vnet_netgraph_uninit().  It can be
triggered trivially by ng_ether since ng_ether_shutdown() persists the
node unless NG_REALLY_DIE is set.

PR:		233622
Reviewed by:	afedorov, kp, Lutz Donnerhacke

(cherry picked from commit cd698c51790e956fed0975f451d3dfc361dc7c24)

Git Hash:   62489e19ebe287034833d07aeb74ca0f0599be6e
Git Author: markj@FreeBSD.org
END